Faculty of Biology - Evolutionary Biology
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Dr. Rienk Fokkema

Office: VHF-353a
Phone: +49 (0)521-106 2831
email: rienk.fokkema"at"uni-bielefeld.de

Current project

My current project focuses on explaining the vast variation in lifetime reproductive success between individuals in natural populations. To understand evolution it is essential to unravel the causes of the variation in this key fitness measure.

Researchers debate on whether individuals differ in their reproductive performance from others due to their genes and environmental conditions experienced in the past (individual quality) or due to current environmental conditions (environmental quality). What is missing in this debate is that the individual and its environment can be tightly intertwined. Through intraspecific competition, individual and environmental quality can become correlated (phenotype-environment correlations).

In my project, I aim to combine analyses of long-term datasets of songbird populations with field experiments. These will shed light on the contributions of individual quality versus environmental quality to variation in individual reproductive success when phenotype-environment correlations are accounted for. The overall aim of my research is to improve our understanding of the evolutionary potential of natural populations.

Research background/interests

I am very much interested in understanding the feedback between individual (fitness) traits and the (social) environment.

My PhD project focused on unravelling the complex interplay between the social environment and parental reproductive effort. Previous work has shown that the occurrence of the trade-off between current and future reproduction may be mediated by the level of competition in the parents? social environment. Only under high competition, parents may pay a cost of reproduction.

I set out to test experimentally whether 1) reproductive effort may negatively affect future parental competitive ability and 2) if so, whether under high levels of competition, this results in the occurrence of costs of reproduction.


since Oct 2017 Postdoctoral fellow, Bielefeld University, Germany, Evolutionary Biology and Animal Behaviour department. Hosted by: PD. Dr. T. Schmoll and Dr. P. Korsten Competitive fellowship provided by the Bielefeld Young Researchers Fund for one full year.
2012-2017 PhD student (thesis approved: 23.05.2017, defence date: 29.09.2017), University of Groningen, NL, Faculty of Science and Engineering, Conservation Ecology group. Supervisors: Prof. J.M. Tinbergen & Prof. C. Both.
2009-2011 MSc Ecology & Evolution, Top master program, completed with distinction, Faculty of Science and Engineering, University of Groningen, NL. (31.10.2011).
2006-2009 BSc Biology, Major Ecology & Evolution, Faculty of Science and Engineering, University of Groningen, NL (31.08.2009).